Microstructure and property evolution of Al-0.4Fe-0.15Zr-0.25Er alloy processed by high pressure torsion

An Al-0.4Fe-0.15Zr-0.25Er alloy was processed by high pressure torsion (HPT) at room temperature in order to explore the evolution of property, microstructure and texture during HPT. The evolution of microstructure revealed by electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). The microhardness increases with increasing strain up to 60 HV at a strain of about 12, and then decreases slightly to a steady stage. HPT processing leads to a significant increase (>100%) in microhardness at expense of a slight reduction (<3%) in electrical conductivity. The synchronous improvement in microhardness and electrical conductivity is obtained after aging. A significant decrease from 40 μm to 600 nm in grain size is observed after HPT deformation for 5 turns and beyond. HPT processing might accelerate the dissolution of the Al3(Zr,Er) precipitate. The A- {111} <110>and C- {001} <110> texture components are dominating after 0.25 turn. After 1 turn, the A and C components weaken, and the {112} <111> new component appears. The texture is weak and close to random due to recovery and recrystallization after 5 turns and beyond.